数字波束形成-DBF

摘要I摘要随着高速、超高速信号采集、传输及处理技术的发展,数字阵列雷达已成为当代雷达技术发展的一个重要趋势。数字波束形成(DBF)技术采用先进的数字信号处理技术对阵列天线接收到的信号进行处理,能够极大地提高雷达系统的抗干扰能力,是新一代军用雷达提高目标检测性能的关键技术之一。并且是无线通信智能天线中的核心技术。本文介绍了数字波束形成技术的原理，对波束形成的信号模型进行了详细的推导，并且用matlab仿真了三种计算准则下的数字波束形成算法，理论分析和仿真结果表明以上三种算法都可以实现波束形成，并对三种算法进行了比较。同时研究了窄带信号的自适应波束形成的经典算法。研究并仿真了基于最小均方误差准则的LMS算法、RLS算法和MVDR自适应算法，并且做了一些比较。关键词：数字波束形成、自适应波束形成、智能天线、最小均方误差、最大信噪比、最小方差ABSTRACTIIABSTRACTWiththedevelopmentofhigh-speed,ultrahigh-speedsignalacquisition,transmissionandprocessingtechnology,digitalarrayradarhasbecameanimportanttrendinthedevelopmentofmodernradartechnology.Digitalbeamforming(DBF)technologyusesadvanceddigitalsignalprocessingtechnologytoprocessthesignalreceivedbyantennaarray.Itcanimprovetheanti-jammingabilityofradarsystemgreatlyanditisoneofthekeytechnology。Itisthecoreofthesmartantennatechnologyinwirelesscommunicationtoo。Thispaperintroducestheprincipleofdigitalbeamformingtechnology,thesignalmodelofbeamformingwaspresented,AndthedigitalbeamformingalgorithmunderthethreecalculationcriterionwassimulatedbyMATLAB,theoreticalanalysisandsimulationresultsshowthatthethreealgorithmscanachievebeamforming,andmadesomecomparisonbetweenthethreealgorithms.Atthesametime,madesomestudyabouttheadaptivenarrow-bandsignalbeamformingalgorithm.LearnedandSimulatededtheLMSalgorithmbaseonminimummeansquareerrorcriterionandRLSalgorithmandMVDRalgorithm,anddosomecomparisonKeyWords:DBF,ADBF,Smartantenna,Theminimummeansquareerror,Themaximumsignaltonoiseratio目录III目录第1章绪论........................................................11.1背景介绍.............................................................................................................11.1.1数字波束形成在国内外的发展及现状...................................................11.1.2展望...........................................................................................................31.2论文内容............................................................................................................4第2章DBF原理及应用..............................................52.1窄带信号模型.....................................................................................................52.2空间匹配滤波器................................................................................................62.3阵列方向图........................................................................................................72.4阵列增益............................................................................................................92.5波束宽度..........................................................................................................102.6相位扫描的带宽限制......................................................................................102.7智能天线...........................................................................................................112.7.1天线结构..................................................................................................112.7.2实现原理..................................................................................................112.7.3技术分类.................................................................................................122.7.4应用领域.................................................................................................132.8本章小结..........................................................................................................14第3章最优波束形成准则...........................................153.1最小均方误差准则..........................................................................................153.2最大信噪比准则..............................................................................................173.3线性约束最小方差（LCMV）准则..............................................................18目录IV3.4仿真结果..........................................................................................................193.4.1mmse准则下的仿真...............................................................................193.4.2MSNR准则下的仿真.............................................................................203.4.3LCMV准则下的仿真.............................................................................213.5三种准则的对比..............................................................................................223.6本章总结...........................................................................................................23第4章自适应波束形成算法.........................................244.1经典自适应波束形成算法..............................................................................244.2最小均方(LMS)算法.......................................................................................254.3递归最小二乘（RLS）算法..........................................................................264.4最小方差无畸变响应(MVDR).......................................................................274.5经典自适应算法的仿真..................................................................................284.5.1LMS算法的仿真....................................................................................284.5.2RLS算法仿真.........................................................